The present invention relates to a narrow-pitch connector for connecting terminals with each other, a pitch converter, a micro-machine, a piezoelectric actuator, an electrostatic actuator, an ink et head, an ink jet printer, a liquid crystal device electronic equipment.
Recently, electronic equipment has been developed remarkably, and the degree of integration per unit area has been enhanced as the electronic equipment has been made smaller in size, lighter in weight and larger in capacity. In the present circumstances, however, the technical advance of peripheral portions of the electronic equipment lags behind relatively, and there is no proposal particularly to make terminal electrodes of a connection portion finer.
Connecting subjects such as printer heads (hereinafter referred to as xe2x80x9cprinter engine portionsxe2x80x9d) having piezoelectric elements for blasting ink by the vibration of the piezoelectric elements, LCD cells of liquid crystal devices, or the like, have been made finer year by year, so that the interval between terminal electrodes has become narrower correspondingly. To connect a driving circuit to such a connecting subject, a tape carrier package is hitherto attached to convert the pitch of a wiring pattern so as to make a connection with the driving circuit.
This connection will be described in detail with reference to the drawings. FIG. 17 is a main portion enlarged view of a connecting subject and a tape carrier package. As shown in FIG. 17, in a connecting subject 1 such as a printer engine portion, an LCD cell of a liquid crystal device, or the like, a plurality of wirings 2 connected with elements are drawn around on the surface of the connecting subject 1, and terminal electrodes 3 are formed in end portions of the connecting subject 1.
On the other hand, a tape carrier package 4 for making a connection with the connecting subject 1 is formed of a flexible substrate the material of which is composed of polyimide. Terminal electrodes 5 which can be put on the terminal electrodes 3 respectively formed in the end portions of the connecting subject 1 are formed at one end of this substrate while terminal electrodes 6 which are wider than the terminal electrodes 5 and which are disposed at larger intervals than the terminal electrodes 5 are formed in the end portion opposite to the terminal electrodes 5. A semiconductor device 6A for driving the connecting subject 1 is provided between the terminal electrodes 5 and the terminal electrodes 6. This semiconductor device 6A is received in a hole portion (device hole) which is provided in a substantially central portion of the tape carrier package 4. The other end portions of wirings constituting the terminal electrodes 5 and the terminal electrodes 6 are made to project from the hole portion so as to form inner leads. The inner leads are connected with terminals provided in the semiconductor device 6A so that the terminal electrodes 5 and the terminal electrodes 6 are made electrically conductive with the semiconductor device 6A.
FIG. 18 is an explanatory view showing the process of connecting the connecting subject 1 with the tape carrier package 4. As shown in FIG. 18, in the case where the aforementioned connecting subject 1 and the aforementioned tape carrier package 4 are connected with each other, the connecting subject 1 is first disposed on a bonding stage 7 so that the terminal electrodes 3 are located on the upper surface side. Next, positioning is performed between the terminal electrodes 5 provided on the tape carrier package 4 and the aforementioned terminal electrodes 3 so that both the terminal electrodes are put on top of each other. Incidentally, a bonding agent containing electrically conductive particles are applied between the terminal electrodes 3 and the terminal electrodes 5 so that both the terminal electrodes are made electrically conductive with each other through the electrically conductive particles.
Here, a bonding tool 8 which can move up and down is provided above the position where both the electrodes are put on top of each other, that is, above the terminal electrodes 5 in the tape carrier package 4. Incidentally, the bonding tool 8 includes a heater 9 so that a front end portion of the bonding tool 8 can be heated by operating this heater 9.
By moving down the bonding tool 8 configured thus, both the electrodes are connected with each other while not only is it intended to bring both the electrodes into close contact with the electrically conductive particles but also it is intended to shorten the time to dry the bonding agent by heating. Incidentally, when both the electrodes are connected with each other, the bonding agent containing electrically conductive particles is not always required. Both the electrodes may be welded or metal-bonded by applying pressure and heat to the electrodes which are put on top of each other without using any bonding agent.
Incidentally, although a printer head (printer engine portion) using a piezoelectric element or an LCD cell of a liquid crystal device was described here by way of example, bonding may be performed by a similar technique also in a micro-machine in which a fine moving mechanism portion is formed on a substrate and a wiring for transferring energy (for applying a voltage) to this moving mechanism portion is extracted, a piezoelectric actuator using a piezoelectric element, an electrostatic actuator using an electrostatic vibrator, a printer head using an electrostatic actuator, a printer using such actuators, and electronic equipment mounted with such apparatus.
However, in the tape carrier package or the terminal electrode connecting method described above, there have been technical problems as follows.
FIGS. 19(a) and (b) show sectional views respectively taken on line Cxe2x80x94C in FIG. 18, in which an interval 10 between the terminal electrodes 3 is made narrower correspondingly to the fact that the connecting subject 1 such as a printer engine portion, an LCD cell of a liquid crystal device, or the like, has been made finer year by year as described above. As a result, if the material composing the connecting subject 1 (mainly silicon) and the material composing the tape carrier package 4 (mainly polyimide) are different in thermal expansion coefficient, the thermal expansion of the tape carrier package 4 becomes larger due to the influence of the heater 9 included in the bonding tool 8 when the bonding tool 8 is made close to the connecting subject 1 and the tape carrier package 4 in order to bond them. As a result, as shown in FIG. 19(b), the terminal electrodes 5 are displaced relatively to the terminal electrodes 3 respectively. Thus, there has been a fear that there arises a problem such as increase in resistance value or failure in bonding between both the terminals, or short-circuit with adjacent terminals. Incidentally, according to various investigations made by the present inventor, it was confirmed that there was a limit of a wiring pitch near 60 xcexcm in a tape carrier package made of polyimide material.
Incidentally, the semiconductor device 6A provided in the inside of the tape carrier package 4 is not in tight contact with the tape carrier package 4. Therefore, there has been a problem that the semiconductor device 6A has no effect of heat transfer to the tape carrier package 4, so that the heat radiation from the semiconductor device 6A is not performed effectively. In addition, the inner leads which will be wiring end portions project from the device hole, and are connected with the terminals of the semiconductor device 6A so as to make an electric connection with the semiconductor device 6A. However, the inner leads also have a function to mechanically hold the semiconductor device in the device hole. Therefore, if the semiconductor device 6A moves in the device hole (due to external force or the like), there has been a fear that the inner leads adjacent to each other abut against each other so as to cause an obstruction such as short-circuit or the like. Therefore, in order to protect the inner leads, application of sealer to the semiconductor device 6A and the inner leads is required after they are bonded with each other, so that the circumference of the device hole including the semiconductor device 6A are sealed. That is, a drying/solidifying process is required for solidifying the sealer. Thus, the increase of the manufacturing process has come into problem.
On the other hand, in an actuator, or the like, manufactured by use of a micro-machine or micro-machining technique, it has been inevitable that the area of wiring terminals increases in comparison with a moving mechanism portion or an actuator portion because the actuator is connected with an external board by a method of flexible-substrate or wire bonding, wire cable soldering, or the like. In order to form such a moving mechanism portion or such an actuator, precise machining represented by anisotropic etching is required, and an expensive material or an expensive machine is also required. It is therefore desired that the area of wiring terminal portions is made so minimal that the moving mechanism portion or actuator is manufactured efficiently.
It is an object of the present invention to provide a narrow-pitch connector in which the positional deviation between terminal electrodes to be connected with each other can be reduced even if thermal stress is applied, in which effective heat radiation from a semiconductor device mounted on the connector can be achieved and which can be manufactured easily; a pitch converter; a micro-machine; a piezoelectric actuator; an electrostatic actuator; an ink jet head; an ink jet printer; a liquid crystal device; and electronic equipment.
(1) According to an aspect of the present invention, there is provided a narrow-pitch connector in which a plurality of first terminal electrodes and a plurality of second terminal electrodes are formed on a substrate, and a first wiring connected with the first terminal electrodes and a second wiring connected with the second terminal electrodes are formed; wherein the narrow-pitch connector comprises a semiconductor device which is electrically connected with the first wiring and the second wiring, a pitch of the first terminal electrodes is narrower than a pitch of the second terminal electrodes, and the number of the first terminal electrodes is larger than the number of the second terminal electrodes.
(2) According to another aspect of the present invention, in the narrow-pitch connector stated in the above paragraph (1), the substrate is formed of silicon.
(3) According to another aspect of the present invention, in the narrow-pitch connector stated in the above paragraph (1), the semiconductor device is disposed so that long sides of the semiconductor device are put substantially in parallel with an alignment direction of the first terminal electrodes.
(4) According to another aspect of the present invention, in the narrow-pitch connector stated in the above paragraph (1), the semiconductor device is disposed so that short sides of the semiconductor device are put substantially in parallel with an alignment direction of the first terminal electrodes.
(5) According to another aspect of the present invention, in the narrow-pitch connector stated in the above paragraph (1), an insulating layer is provided on the substrate so as to be formed at least in an area where the semiconductor device is disposed, and the first wiring and the second wiring are formed on the insulating layer.
In the respective inventions of the above paragraphs (1) to (5), if silicon is used as the material for the substrate of the narrow-pitch connector, the narrow-pitch connector can be formed of a material the thermal expansion coefficient of which is smaller than that of a material of a flexible substrate, and further in the same manner as the process for forming a semiconductor device. In addition, the wirings with a narrow pitch can be formed easily. Further, silicon is so high in heat conductivity that the effect of heat radiation can be enhanced. Therefore, the narrow-pitch connector can be prevented from temperature rising due to heat generated in the semiconductor device.
In addition, the semiconductor device may be disposed so that the long sides of the semiconductor device are substantially parallel with the alignment direction of the first terminal electrodes, or disposed so that the short sides of the semiconductor device are substantially parallel with the alignment direction of the first terminal electrodes. In the latter case, the width of the narrow-pitch connector can be reduced.
In addition, because the semiconductor device adheres closely onto the substrate of the narrow-pitch connector through an insulating layer, even if heat is generated in the semiconductor device, the heat generated in the semiconductor device is transferred to the substrate and then radiated from the substrate. Thus, not only the surface of the semiconductor device but also the surface of the substrate serve for heat radiation. Accordingly, even if the heating value of the semiconductor device is large, heat radiation can be performed satisfactorily. Further, because the substrate can be made to hold the semiconductor device, it becomes easy to ensure the mechanical strength.
In addition, the respective electrodes of the semiconductor device are connected to wirings along (in tight contact with) the surface of the substrate differently from inner leads which are cantilever-supported. Accordingly, there is no fear that the semiconductor device moves after connection. As a result, application of sealer to the semiconductor device is not required. Thus, not only is it possible to eliminate a drying process and so on, but also there is no fear that short-circuit is caused between terminals due to the movement of the semiconductor device.
(6) According to another aspect of the present invention, there is provided a pitch converter comprising: a narrow-pitch connector in which a plurality of first terminal electrodes and a plurality of second terminal electrodes are formed on a substrate, and a first wiring connected with the first terminal electrodes and a second wiring connected with the second terminal electrodes are formed; and a connecting subject having external terminal electrodes electrically connected with the first terminal electrodes; wherein a semiconductor device electrically connected with the first wiring and the second wiring is provided, a pitch of the first terminal electrodes is narrower than a pitch of the second terminal electrodes, and the number of the first terminal electrodes is larger than the number of the second terminal electrodes.
(7) According to another aspect of the present invention, in the above pitch converter, the substrate has a characteristic that a thermal expansion coefficient thereof is substantially equal to or smaller than a thermal expansion coefficient of the connecting subject.
(8) According to another aspect of the present invention, in the above pitch converter, the substrate and the connecting subject are formed of one and the same material.
(9) According to another aspect of the present invention, in the above pitch converter, the substrate and the connecting subject are formed of silicon.
(10) According to another aspect of the present invention, in the above pitch converter, the first terminal electrodes are electrically connected with the external terminal electrodes through electrically conductive members.
In the respective inventions of the above paragraphs (6) to (10), the substrate of the narrow-pitch connector has a characteristic that the thermal expansion coefficient of the substrate is substantially equal to or smaller than that of the connecting subject. Accordingly, when the first terminal electrodes of the connector and the external terminal electrodes of the connecting subject are connected with each other by pressing and heating, both the electrodes are lengthened by substantially the same quantity so that the relative positional deviation of the electrodes which are put on top of each other can be restrained to the minimum.
In addition, because the substrate of the narrow-pitch connector and the connecting subject are formed of the same material, the relative positional deviation of the electrodes can be restrained when the electrodes are put on top of each other.
Further, because silicon which is high in heat conductivity is used as the material of the substrate of the narrow-pitch connector and the connecting subject, the effect of heat radiation can be more enhanced so that the resistance value can be prevented from increasing due to temperature rising.
Moreover, because the first terminal electrodes of the connector and the external terminal electrodes of the connecting subject are connected with each other through the electrically conductive members, the electric connection between both the electrodes can be made more reliable. Incidentally, for example, if an anisotropic conductive film made by forming an anisotropic conductive bonding agent into a thin film is used as the electrically conductive members, the electrically conductive members can be prevented from projecting from the bonding portion.
(11) According to another aspect of the present invention, there is provided a micro-machine comprising a first substrate in which a moving mechanism portion and a plurality of external terminal electrodes are formed, and a second substrate in which first terminal electrodes for making electric connection with the plurality of external terminal electrodes are formed; wherein the second substrate has a plurality of second terminal electrodes, first wiring connected with the first terminal electrodes, second wiring connected with the second terminal electrodes, and a semiconductor device connected with the first wiring and the second wiring; and wherein a pitch of the first terminal electrodes is narrower than a pitch of the second terminal electrodes, and the number of the first terminal electrodes is larger than the number of the second terminal electrodes.
In the invention of the above paragraph (11), in the micro-machine, the first substrate in which the moving mechanism portion of the micro-machine is formed and the second substrate for making a connection with the outside are formed separately. Accordingly, the area of the first substrate can be minimized.
(12) According to another aspect of the present invention, there is provided a piezoelectric actuator comprising a first substrate in which a piezoelectric element and a plurality of external terminal electrodes are formed, and a second substrate having first terminal electrodes for making electric connection with the plurality of external terminal electrodes; wherein the second substrate has a plurality of second terminal electrodes, first wiring connected with the first terminal electrodes, second wiring connected with the second terminal electrodes, and a semiconductor device connected with the first wiring and the second wiring; and wherein a pitch of the first terminal electrodes is narrower than a pitch of the second terminal electrodes, and the number of the first terminal electrodes is larger than the number of the second terminal electrodes.
(13) According to another aspect of the present invention, there is provided an electrostatic actuator comprising a first substrate in which an electrostatic vibrator and a plurality of external terminal electrodes are formed, and a second substrate having first terminal electrodes for making electric connection with the plurality of external terminal electrodes; wherein the second substrate has a plurality of second terminal electrodes, first wiring connected with the first terminal electrodes, second wiring connected with the second terminal electrodes, and a semiconductor device connected with the first wiring and the second wiring; and wherein a pitch of the first terminal electrodes is narrower than a pitch of the second terminal electrodes, and the number of the first terminal electrodes is larger than the number of the second terminal electrodes.
(14) According to another aspect of the present invention, there is provided an ink jet head including the piezoelectric actuator stated in the above paragraph (12). (15) According to another aspect of the present invention, there is provided an ink jet head including the electrostatic actuator stated in the above paragraph (13).
(16) According to another aspect of the present invention, there is provided an ink jet printer including an ink jet head stated in the above paragraph (14).
(17) According to another aspect of the present invention, there is provided an ink jet printer including an ink jet head stated in the above paragraph (15).
In the respective inventions of the above paragraphs (12), (14) and (16), the first substrate in which a piezoelectric element is formed and the second substrate for making a connection with the outside are formed separately. Accordingly, the area of the first substrate can be minimized.
On the other hand, in the respective inventions of the above paragraphs (13), (15) and (17), the first substrate in which an electrostatic vibrator is formed and the second substrate for making a connection with the outside are formed separately. Accordingly, the area of the first substrate can be minimized.
(18) According to another aspect of the present invention, there is provided a liquid crystal device in which a liquid crystal is held between a first substrate and a second substrate and in which a plurality of external terminal electrodes are formed on one of the first and second substrates; wherein a third substrate having first terminal electrodes for making electric connection with the plurality of external terminal electrodes is provided; wherein the third substrate has a plurality of second terminal electrodes, first wiring connected with the first terminal electrodes, second wiring connected with the second terminal electrodes, and a semiconductor device connected with the first wiring and the second wiring; and wherein a pitch of the first terminal electrodes is narrower than a pitch of the second terminal electrodes, and the number of the first terminal electrodes is larger than the number of the second terminal electrodes.
In the invention of the above paragraph (18), the so-called liquid crystal cell in which the liquid crystal is held between the first substrate and the second substrate and in which a plurality of external terminal electrodes are formed in one of the first and second substrates, and the third substrate for making a connection with the outside are formed separately. Accordingly, the area occupied by the external terminal electrodes in the liquid crystal cell can be minimized. Therefore, a large liquid crystal display portion can be ensured in the liquid crystal cell even if the liquid crystal cell having the same area as that of a background-art one is used. In addition, because the number of terminals in a connecting portion can be increased easily, the pitch of picture elements can be reduced so that the picture elements can be made precise extremely.
(19) According to another aspect of the present invention, there is provided an electronic equipment comprising a liquid crystal device; wherein the liquid crystal device is arranged so that a liquid crystal is held between a first substrate and a second substrate and a plurality of external terminal electrodes are formed on one of the first and second substrates; wherein a third substrate having first terminal electrodes for making electric connection with the plurality of external terminal electrodes is provided; wherein the third substrate has a plurality of second terminal electrodes, first wiring connected with the first terminal electrodes, second wiring connected with the second terminal electrodes, and a semiconductor device connected with the first wiring and the second wiring; and wherein a pitch of the first terminal electrodes is narrower than a pitch of the second terminal electrodes, and the number of the first terminal electrodes is larger than the number of the second terminal electrodes.
In the invention of the above paragraph (19), the electronic equipment has the liquid crystal device which comprises the so-called liquid crystal cell, in which the liquid crystal is held between the first substrate and the second substrate and in which a plurality of external terminal electrodes are formed in one of the first and second substrates, and the third substrate for making a connection with the outside, and the liquid crystal cell and the third substrate are formed separately. Accordingly, the area occupied by the external terminal electrodes in the liquid crystal cell can be minimized. As a result, miniaturization of the electronic equipment becomes easy.